Accurate sticking coefficient calculation for carbonaceous dust growth through accretion and desorption in astrophysical environments,Astronomy & Astrophysics

当前位置： X-MOL 学术 › Astron. Astrophys. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Accurate sticking coefficient calculation for carbonaceous dust growth through accretion and desorption in astrophysical environments
Astronomy & Astrophysics ( IF 5.4 ) Pub Date : 2024-12-18 , DOI: 10.1051/0004-6361/202452362
D. Bossion, A. Sarangi, S. Aalto, C. Esmerian, S. R. Hashemi, K. K. Knudsen, W. Vlemmings, G. Nyman

Context. Cosmic dust is ubiquitous in astrophysical environments, where it significantly influences the chemistry and the spectra. Dust grains are likely to grow through the accretion of atoms and molecules from the gas-phase onto them. Despite their importance, only a few studies have computed the sticking coefficients for relevant temperatures and species, along with their direct impact on grain growth. Overall, the formation of dust and its growth are not well understood.Aims. This study is aimed at calculating the sticking coefficients, binding energies, and grain growth rates over a broad range of temperatures, for various gas species interacting with carbonaceous dust grains.Methods. We performed molecular dynamics simulations with a reactive force field algorithm to compute accurate sticking coefficients and obtain the binding energies. These results were used to build an astrophysical model of nucleation regions to study dust growth.Results. We present, for the first time, the sticking coefficients of H, H_{2_{, C, O, and CO on amorphous carbon structures for temperatures ranging from 50 K to 2250 K. In addition, we estimated the binding energies of H, C, and O in carbonaceous dust to calculate the thermal desorption rates. Combining accretion and desorption allows us to determine an effective accretion rate and sublimation temperature for carbonaceous dust.Conclusions. We find that sticking coefficients can differ substantially from what is commonly used in astrophysical models. This offers us new insights into carbonaceous dust grain growth via accretion in dust-forming regions.}}

中文翻译：

在天体物理环境中通过吸积和解吸生长的碳质尘埃的准确粘附系数计算

上下文。宇宙尘埃在天体物理环境中无处不在，它对化学和光谱有重大影响。尘埃颗粒很可能是通过原子和分子从气相吸积到它们上而生长的。尽管它们很重要，但只有少数研究计算了相关温度和物种的粘附系数，以及它们对谷物生长的直接影响。总体而言，尘埃的形成及其生长尚不清楚。目标。本研究旨在计算与碳质尘粒相互作用的各种气体种类在较宽温度范围内的粘附系数、结合能和晶粒生长速率。方法。我们使用反作用力场算法进行了分子动力学模拟，以计算准确的粘附系数并获得结合能。这些结果被用来构建成核区域的天体物理模型，以研究尘埃的增长。结果。我们首次提出了 H、H _{2_{, C, O, and CO on amorphous carbon structures for temperatures ranging from 50 K to 2250 K. In addition, we estimated the binding energies of H, C, and O in carbonaceous dust to calculate the thermal desorption rates. Combining accretion and desorption allows us to determine an effective accretion rate and sublimation temperature for carbonaceous dust.Conclusions. We find that sticking coefficients can differ substantially from what is commonly used in astrophysical models. This offers us new insights into carbonaceous dust grain growth via accretion in dust-forming regions.}} 的粘附系数